BACKGROUND: The most effective treatment for anal fistula is fistulotomy, but it involves a risk of anal incontinence. To reduce this morbidity, sphincter-sparing treatments have been developed, but their success in real life is often less than 50%. The aim is to determine clinical healing rate 6 months after radiofrequency treatment. PATIENTS AND METHODS: We planned to evaluate 50 patients from 3 French proctology centres. Treatment efficacy was evaluated at 6 and 12 months by means of clinical and magnetic resonance imaging examination. We evaluated morbidity and healing prognostic factors. RESULTS: Fifty patients with a mean age of 51years [22-82] were included. Eleven patients had a low transsphincteric fistula(LTS), 21 high transsphincteric fistula(HTS), 8 complex fistula and 9 Crohn’s disease fistula. After 6 months, 17 patients (34.7%) had a clinically healed fistula, including 5 (45.5%) with LTS fistula, 7 (33.3%) with HTS fistula, 1 (12.5%) with complex fistula, 4 (44.4%) with Crohn’s disease, with no significant difference between these fistula types (p:0.142). At 12 months, the healing rate was identical. MRI in 15 out of 17 clinically healed patients showed a deep remission of 73.3% at 12 months. Energy power was associated with the success of the treatment. There was an 8.2% incidence of post-surgical complications with 4.1% being abscesses (one required surgical management). Postoperative pain was minor. No new cases or deterioration of continence have been shown. CONCLUSION: Radiofrequency is effective in less than 50% of the cases as an anal fistula treatment in this first prospective study, with low morbidity and no effect on continence. Clinical healing was deep (MRI) in ¾ at 1 year. The increase in energy power during the procedure seems to be a key point to be analysed to optimise results.